Plant control apparatus, plant control method, and non-transitory computer-readable recording medium

Abstract

In accordance with an embodiment, a plant control apparatus includes a deviation calculation unit, a velocity-type PID calculation unit, a plurality of integral calculation units, a plurality of overwrite units, and an automatic balance unit. The deviation calculation unit calculates a deviation between a process value from a plant with operation terminals and a set value corresponding to a control object, and generates a deviation signal. The velocity-type PID calculation unit generates a velocity-type operation amount command signal corresponding to the deviation. The integral calculation units generate position command signals as defined operation terminal position command signals. The overwrite units generate additional position command signals to perform overwrite processing and newly define operation terminal position command signals. The automatic balance unit calculates a deviation between the defined operation terminal position command signals, corrects the operation amount command signal and supplies the corrected operation amount command signal.

The invention claimed is: 
     
       1. A plant control apparatus comprising:
 a deviation calculation processor programmed to calculate a deviation between a process value supplied from a plant to be controlled and a set value corresponding to a control object, and to generate a deviation signal, the plant comprising a plurality of operation terminals; 
 a velocity-type PID calculation processor programmed to perform a PID calculation on receipt of the deviation signal from the deviation calculation processor, and to generate a velocity-type PID operation amount command signal corresponding to the deviation; 
 a plurality of integral calculation processors provided in association with the number of the operation terminals and programmed to generate position command signals for the respective operation terminals as defined operation terminal position command signals in accordance with the operation amount command signal; 
 a plurality of overwrite processors provided to respectively correspond to the integral calculation processors and programmed to generate additional position command signals for the respective operation terminals, to perform overwrite processing for the corresponding integral calculation processors and to newly define operation terminal position command signals; and 
 an automatic balance processor programmed to be supplied with the velocity-type PID operation amount command signal from the velocity-type PID calculation processor, to be supplied with the defined operation terminal position command signals from the respective integral calculation processors, to compare the defined operation terminal position command signals, each corresponding to the respective operation terminals, with one another, to calculate a deviation between the defined operation terminal position command signals when the defined operation terminal position command signals are not equal to each other, to correct the operation amount command signal in accordance with a result of the calculation, and to supply the corrected operation amount command signal to the corresponding integral calculation processors. 
 
     
     
       2. The apparatus of  claim 1 ,
 wherein the overwrite processors generate overwrite processing signals during overwrite processing and supply the overwrite processing signals to the automatic balance processor, 
 the automatic balance processor corrects the operation amount command signal in accordance with the calculation result of the deviation between the defined operation terminal position command signals when all the overwrite processing signals are switched off after the overwrite processing signals are supplied to the automatic balance processor from at least one of the overwrite processors, and 
 the automatic balance processor stops operation when the deviation between the defined operation terminal position command signals is eliminated as a result of the output of the corrected operation amount command signal. 
 
     
     
       3. The apparatus of  claim 2 ,
 wherein the automatic balance processor uses a predetermined fixed value to correct the operation amount command signal when a deviation is found between the defined operation terminal position command signals. 
 
     
     
       4. The apparatus of  claim 2 ,
 wherein the automatic balance processor uses a variable value corresponding to the deviation between the defined operation terminal position command signals to correct the operation amount command signal when a deviation is found between the defined operation terminal position command signals. 
 
     
     
       5. The apparatus of  claim 1 ,
 wherein the automatic balance processor supplies the operation amount command signal to the integral calculation processors as it is when the overwrite processors are not performing overwrite processing. 
 
     
     
       6. The apparatus of  claim 1 ,
 wherein the automatic balance processor corrects the operation amount command signal when the deviation between the defined operation terminal position command signals is beyond a predetermined dead band. 
 
     
     
       7. The apparatus of  claim 6 ,
 wherein the automatic balance processor uses a predetermined fixed value to correct the operation amount command signal. 
 
     
     
       8. The apparatus of  claim 6 ,
 wherein the automatic balance processor uses a variable value corresponding to the deviation between the defined operation terminal position command signals to correct the operation amount command signal. 
 
     
     
       9. The apparatus of  claim 6 ,
 wherein the overwrite processors generate overwrite processing signals during overwrite processing and supply the overwrite processing signals to the automatic balance processor, 
 the automatic balance processor calculates a deviation between the defined operation terminal position command signals to correct the operation amount command signal on receipt of the overwrite processing signal from at least one of the overwrite processors, and 
 the automatic balance processor stops operation when the deviation between the defined operation terminal position command signals falls within the dead band as a result of the output of the corrected operation amount command signal. 
 
     
     
       10. A plant control method comprising:
 calculating a deviation between a process value supplied from a plant to be controlled and a set value corresponding to a control object, and then generating a deviation signal, the plant comprising a plurality of operation terminals; 
 performing a PID calculation from the deviation signal, and generating a velocity-type PID operation amount command signal corresponding to the deviation; 
 performing an integral calculation from the operation amount command signal and generating position command signals for the respective operation terminals as defined operation terminal position command signals in a case of an automatic mode; 
 generating additional position command signals for the respective operation terminals and overwriting the corresponding integral calculation and newly defining operation terminal position command signals when at least one of the operation terminals has shifted from the automatic mode to an overwrite mode; and 
 when canceling the entire overwrite mode and returning to the automatic mode, comparing the defined operation terminal position command signals, each corresponding to the respective operation terminals, with one another, calculating a deviation between the defined operation terminal position command signals when the defined operation terminal position command signals are not equal to each other, correcting the operation amount command signal in accordance with a result of the calculation, performing the integral calculation from the corrected operation amount command signal, and generating position command signals for the respective operation terminals as newly defined operation terminal position command signals. 
 
     
     
       11. The method of  claim 10 ,
 wherein the correction of the operation amount command signal is started when a deviation is found between the defined operation terminal position command signals. 
 
     
     
       12. The method of  claim 11 ,
 wherein the correction of the operation amount command signal is made by use of a predetermined fixed value. 
 
     
     
       13. The method of  claim 11 ,
 wherein the correction of the operation amount command signal is made by use of a variable value corresponding to the deviation between the defined operation terminal position command signals. 
 
     
     
       14. The method of  claim 11 ,
 wherein the correction of the operation amount command signal is made until the deviation between the defined operation terminal position command signals is eliminated. 
 
     
     
       15. The method of  claim 10 ,
 wherein the correction of the operation amount command signal is started when the deviation between the defined operation terminal position command signals is beyond a predetermined dead band. 
 
     
     
       16. The method of  claim 15 ,
 wherein the correction of the operation amount command signal is made by use of a predetermined fixed value. 
 
     
     
       17. The method of  claim 15 ,
 wherein the correction of the operation amount command signal is made by use of a variable value corresponding to the deviation between the defined operation terminal position command signals. 
 
     
     
       18. The method of  claim 10 ,
 wherein the correction of the operation amount command signal is made until the deviation between the defined operation terminal position command signals falls within a predetermined dead band. 
 
     
     
       19. A non-transitory computer-readable recording medium in which a program that causes a computer to carry out plant control is stored, the plant control comprising:
 calculating a deviation between a process value supplied from a plant to be controlled and a set value corresponding to a control object, and then generating a deviation signal, the plant comprising a plurality of operation terminals; 
 performing a PID calculation from the deviation signal, and generating a velocity-type PID operation amount command signal corresponding to the deviation; 
 performing an integral calculation from the operation amount command signal and generating position command signals for the respective operation terminals as defined operation terminal position command signals in a case of an automatic mode; 
 generating additional position command signals for the respective operation terminals and overwriting the corresponding integral calculation and newly defining operation terminal position command signals when at least one of the operation terminals has shifted from the automatic mode to an overwrite mode; and 
 when canceling the entire overwrite mode and returning to the automatic mode, comparing the defined operation terminal position command signals, each corresponding to the respective operation terminals, with one another, calculating a deviation between the defined operation terminal position command signals when the defined operation terminal position command signals are not equal to each other, correcting the operation amount command signal in accordance with a result of the calculation, performing the integral calculation from the corrected operation amount command signal, and generating position command signals for the respective operation terminals as newly defined operation terminal position command signals.